Silicon oxide films have been deposited on silicon wafers at low temperature by irradiation of the substrates with an ArF (A = 193 nm) excimer laser beam in a SiH, and N20 atmosphere. A systematic study of the growth rate and properties of the films as a function of the processing parameters (gas cornposition, substrate temperature, laser pulse energy, pulse repetition rate, total pressure and gas flow rate) has been performed. The process is photolytically activated in the gas phase and the diffusion of photodecomposed precursor species towards the surface plays an important limiting role. The N20/SiH, ratio mainly controls the film composition; for ratios above 40, stoichiometric silica may be obtained, as confirmed by Rutherford backscattering (RBS) measurements. The role of the surface temperature in the growth kinetics is not critical, so that deposition of films is possible down to substrate temperatures as low as 70°C. Nevertheless, the density of the films varies greatly with the substrate temperature. The fact that no Si-H vibration was detected with Fourier transform infrared (FTIR) spectrophotometry is surprising, since hydrogen incorporation is a very typical phenomenon encountered in most silane systems. This effect is probably associated with the ultraviolet photon irradiation of the adsorbed species and the film as it grows, thus breaking bonds and affecting the bond structure of the film. KEYWORDS silicon dioxide; thin films; excimer laser; chemical vapour deposition (CVD)